Max Sleep Duration in Power Save Mode
Gave a question about the implementation of wi-fi (802.11b) power save mode. I am using Intel PRO 2200 card. The ipw2200 driver seems to allow setting into five different power modes. The least power consuming mode is 5 set as
%iwpriv eth1 set_power 5
which is supposed to set the card with timeout value 25ms and sleep time 1000ms (as per ipw2100 specs on sourceforge, since ipw2200 does not mention power save mode).
However, when I sniffed the traffic I found that the card never sleeps more than 100ms (the AP beacon interval) and always wakes up before the next beacon to receive any possible packets. This happens even when it is not sending out any packets, but only receiving.
Is this is a known issue with intel pro 2200 cards that they do not implement power save mode correctly? Or do the linux drivers give incorrect information that these cards can be set to sleep for 1000ms while in reality no more than Beacon Interval (100ms) is possible?
Finally, can anyone point me to a card which is known to implement power save mode correctly and can sleep up to 1s before it wakes up to collect packets from the AP?